Fig. 4

Cell division occurs at the site of filament buckling during invasive growth. a Examples (upper and lower panels) of time-lapse images (GFP sum projections) during invasive growth in 40:1 PDMS ratio, showing cell division site at the location of filament buckling with red lines highlighting the buckling angle. b Cell division site occurs where the filament is buckled. Cells were grown either invasively within PDMS (40:1; Young’s modulus ~ 100 kPa) or on the surface of PDMS (30:1–40:1; Young’s modulus 250–100 kPa), n = 26 and 15, respectively. GFP sum projections were analyzed over time from 5 independent experiments and Sin of angle when the septum formed is shown. Septum formation was observed on average 47 ± 20 min after buckling was evident in invasive cells. Bars indicate SD with p < 0.0001